(i) Technical Field
The present invention relates to a white adjusting device, a white adjusting method and a non-transitory computer readable medium.
(ii) Related Art
From the past, white adjustment known as white balance or the like has been performed on an image. For example, in a photographed image, a white color value changes depending on a light source for illuminating an object to be shot. The white color varying according to this light source is adjusted to a predetermined white color. Of course, in the case of the sunlight, white adjustment is required according to the shooting conditions such as sunny, cloudy, and morning and evening, and white adjustment is performed including light in each of such shooting conditions as the light source. The collapse of the white color balance is visually sensitive, and influences the image quality.
When a used light source is not known at the time of performing such white adjustment, it is necessary to estimate the used light source from an image to be adjusted. As a method for this, the temperature (color temperature) of the light source is estimated from the color of a region considered to be white in an image, based on the correspondence of the color of the light source to the color of light emitted from a black body serving as a heat source, and white adjustment based on the estimated color temperature is performed.
When the chromaticity of a black-body radiation is used, the use of a light source which generates heat is premised. However, for example, a fluorescent light may be used indoors, or a light source equipped with a filter may be used. Even though the color temperature of the light source is estimated based on black-body radiation when these light sources are used, the white color may not be corrected.